Varicella (Chicken Pox)

8/8/2019 Varicella (Chicken Pox)

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Varicella (Chicken Pox) Varicella (Chicken Pox)



Varicella Varicella

Varicella Varicella (chickenpox)(chickenpox)

² ² primary infectionprimary infection

Herpes zoster ( Herpes zoster ( shinglesshingles ) ) ² ² recurrent formrecurrent form

Varicella Varicella (chickenpox)(chickenpox) ² ² primary infectionprimary infection

Herpes zoster ( Herpes zoster ( shinglesshingles ) ) ² ² recurrent formrecurrent form



EtiologyEtiology

Varicella Varicella ² ² Zoster (DNA virus )Zoster (DNA virus )

HumansHumans ² ² only reservoironly reservoir

Only one serotype is knownOnly one serotype is known



E pidemiologyE pidemiology

attack rate of at least 90% among susceptibleattack rate of at least 90% among susceptible

(seronegative ) individuals(seronegative ) individuals children 5children 5² ²9 years9 years -- 50% of all cases50% of all cases



Incubation Period: 10Incubation Period: 10--2121daysdays

Mode of TransmissionMode of Transmission

by respiratory dropletsby respiratory droplets

direct contactdirect contact

linen or fomiteslinen or fomites

vertical vertical transmissiontransmissionduring pregnancy during pregnancy



ContagiousContagious

A day before eruptions A day before eruptions

Until all vesicles are crusted (5Until all vesicles are crusted (5--66thth

day )day )

Immunity Immunity ² ² long lasting long lasting



VZV transmission VZV transmission

inoculation of virus onto the mucosa of URT andinoculation of virus onto the mucosa of URT and

tonsillar lymphoid tissuetonsillar lymphoid tissue

Primary Viremic PhasePrimary Viremic Phase

Secondary Viremic PhaseSecondary Viremic Phase

VZV to upper res piratory VZV to upper res piratory

mucosal sitesmucosal sites

Vesicular lesions Vesicular lesions

PathophysiologyPathophysiology



Clinical ManifestationsClinical Manifestations

In healthy children, the disease is generally mildIn healthy children, the disease is generally mild

IPIP FeverFever ² ² usually low grade preceding skin manifestationusually low grade preceding skin manifestation

malaise, anorexia, headache, cough, runny nose, decreasedmalaise, anorexia, headache, cough, runny nose, decreasedappetiteappetite

Superficial vesicular lesionsSuperficial vesicular lesions ´dewdrop on a rose petalµ´dewdrop on a rose petalµ

PruriticPruritic Trunk, face or trunk Trunk, face or trunk centrifugalcentrifugal

All developmental stages of the rash are present at the same All developmental stages of the rash are present at the sametimetime



LaboratoryLaboratory

Viral Isolation Viral Isolation

yy Vesicular scrapings (Tzanck smear ) Vesicular scrapings (Tzanck smear ) -- multimulti--nucleatednucleatedgiant cells, consistent with VZV and herpes simplexgiant cells, consistent with VZV and herpes simplex virus ( HSV ) infection. virus ( HSV ) infection.

yy fluorescent monoclonal antibody testfluorescent monoclonal antibody test -- very sensitive very sensitiveand specificand specific



Serologic Testing Serologic Testing ----

Antibody Tests: Antibody Tests: Complement fixation ( CF ): Commercially available, but lacksComplement fixation ( CF ): Commercially available, but lacks

sensitivity.sensitivity.

Neutralization test (NT ): Sensitive and specific; timeNeutralization test (NT ): Sensitive and specific; timeconsuming and difficult to perform; not readily available.consuming and difficult to perform; not readily available.

Immunofluorescence assay for antibody to VZV Immunofluorescence assay for antibody to VZV--inducedinducedmembrane antigen (FAMA ): sensitive, time consuming, notmembrane antigen (FAMA ): sensitive, time consuming, notreadily available.readily available.

Immune adherence hemagglutination ( I AH A ) sensitive; notImmune adherence hemagglutination ( I AH A ) sensitive; notreadily available.readily available.

EnzymeEnzyme--linked immunosorbent assay (ELISA ): Sensitive,linked immunosorbent assay (ELISA ): Sensitive,simple, and commercially available; may be useful for routinesimple, and commercially available; may be useful for routinetesting.testing.



Treatment Treatment

Healthy childrenHealthy children

no medical treatmentno medical treatment

antihistamine to relieve itching antihistamine to relieve itching

Oral therapy with acyclovir (20 mg/kg/dose, maximum 800Oral therapy with acyclovir (20 mg/kg/dose, maximum 800

mg/dose ) given as 4 doses/day for 5 days should be used to treatmg/dose ) given as 4 doses/day for 5 days should be used to treatuncomplicated varicellauncomplicated varicella

I V AcyclovirI V Acyclovir (nucleoside analogues ) (nucleoside analogues )

< 1 yr 30 mg/kg/day in 3 divided doses for 7< 1 yr 30 mg/kg/day in 3 divided doses for 7--10 days10 days

>> 1 yr 1500 mg/m1 yr 1500 mg/m22/day divided q 8 h for 7/day divided q 8 h for 7--10 days10 days

Immunocompromised patientsImmunocompromised patients Patients being treated with chronic corticosteroidsPatients being treated with chronic corticosteroids

medications to shorten the duration of the infectionmedications to shorten the duration of the infection

help reduce the risk of complicationshelp reduce the risk of complications

Recommendations of the Advisory Committee on Immunization Practices. MMWR 200 6;55:209-210.



Valacyclovir and Famciclovir Valacyclovir and Famciclovir

approved for use only in adultsapproved for use only in adults

Don't give Aspirin : Reye's syndrome.Don't give Aspirin : Reye's syndrome.



Complications of VaricellaComplications of Varicella

herpes zoster (shingles )herpes zoster (shingles )

lifetime risk 15%lifetime risk 15%--20%20%

mainly affecting themainly affecting the

elderly andelderly andimmunocompromisedimmunocompromisedpersonspersons

secondary bacterial skinsecondary bacterial skin

and soft tissue infectionsand soft tissue infections otitis mediaotitis media

bacteremia,bacteremia, pneumonitispneumonitis

osteomyelitisosteomyelitis

septic arthritisseptic arthritis

endocarditisendocarditis

necrotizing fasciitisnecrotizing fasciitis

toxic shock toxic shock--like syndromelike syndrome

hepatitishepatitis

thrombocytopeniathrombocytopeniahemorrhagic varicellahemorrhagic varicella

cerebellar ataxiacerebellar ataxia

encephalitisencephalitis

severe invasive group Asevere invasive group Astreptococcal infectionstreptococcal infectionincreases the risk increases the risk 4040--6060 foldfold



PreventionPrevention

Live virus varicella vaccineLive virus varicella vaccine -- monovalent vaccinemonovalent vaccine

Measles, mumps, and rubella (MMR ) vaccineMeasles, mumps, and rubella (MMR ) vaccine



PreventionPrevention

VZIG VZIG

Dose: 125 units/I0 kg, up to a maximum of 625Dose: 125 units/I0 kg, up to a maximum of 625units (five vials ), IM. Volume 125 units per 1.25 mlunits (five vials ), IM. Volume 125 units per 1.25 ml(one vial ).(one vial ).

Should be given within 96 hours of exposure,Should be given within 96 hours of exposure,preferably as soon as possiblepreferably as soon as possible



Varicella Vaccine Varicella Vaccine

Oka strainOka strain

between 12 and 15 monthsbetween 12 and 15 months booster shot at 4 to 6 years of agebooster shot at 4 to 6 years of age

77--13 years13 years -- who have not had chickenpox may who have not had chickenpox may also receive the vaccine, with the two dosesalso receive the vaccine, with the two dosesgiven at least 3 months apart.given at least 3 months apart.

13 years who have not had either chickenpox 13 years who have not had either chickenpoxor the vaccine need two vaccine doses at least 1or the vaccine need two vaccine doses at least 1month apart.month apart.

Varicella (Chicken Pox)

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